1. Field of the Invention
The invention relates to a device and method which simplifies the attachment of a prosthetic screen to the abdominal wall during the repair of abdominal wall hernias.
2. Brief Description of the Prior Art
The layer or layers of fascia which lie in the abdominal wall and surround the peritoneal cavity are the strong structures which maintain the integrity of the peritoneal cavity. If there is a defect in the fascia, abdominal contents may penetrate weaker layers of the abdominal wall (comprised of muscle or fat) and push ahead the abdominal cavity's thin lining (peritoneum) so that abdominal contents, such as omentum or bowel, within their envelope of peritoneum, become situated in a subcutaneous position, often causing a visible bulge.
Viscera being squeezed through a fascia defect can cause pain. When a visceral structure becomes trapped outside the fascial plane, it is said to be incarcerated. Incarcerated viscera can be strangulated by a narrow fascial defect, producing ischemic necrosis. This may lead to infection and death if not surgically repaired. Hernias are therefore usually repaired electively, before they become incarcerated or strangulated.
Historically, hernias of the abdominal wall were repaired by closing the fascial defect with sutures. Large hernias tend to recur if closed in this way. Prosthetic screens, made of plastic mesh or sheets, are now frequently used to cover large fascial defects. One way to implant the prosthetic screen is illustrated in prior art FIG. 1. Here, the prosthesis 1 is attached to the fascia 2c of the abdominal wall 2 with sutures 3. This is relatively easy to do, but the repair has a high rate of failure because the sutured prosthesis often pulls away from the fascial edge.
Other ways to secure prosthetic screens are shown in prior art FIGS. 2–5. In each of these methods the prosthesis 1 overlaps the edge of the fascia 2c. These methods are less likely to fail. Increased intra-abdominal pressure tends to force the periphery of the prosthesis against the abdominal wall rather than pull the prosthesis away from the fascia. A gap where both prosthesis and fascia are absent is less likely to develop.
If the prosthetic screen is allowed to overlap the edges of the fascial defect, there are a number of ways it can be secured in place as illustrated in prior art FIGS. 2–5. The sutures 3 can secure the fascia 2c to the prosthesis 1 inward from the edge of the prosthesis as shown in prior art FIG. 2. This is technically easy when the surgery is done in the conventional approach. However materials such as Gortex™ or polypropylene mesh used for prosthetic screens are soft and may buckle and deform outside the suture line, so that the structural advantage of the overlap with fascia is not realized.
A better method is to secure the prosthesis 1 to the abdominal wall fascia 2c with sutures 3 as close to the edge of the prosthesis as possible, while maintaining generous overlap between prosthesis and intact fascia as shown in prior art FIG. 3. However, it can be difficult to secure an overlapping intraperitoneal prosthesis at its periphery when performing surgery using a conventional approach. Access to the inside surface of the abdominal wall overlying the periphery of the prosthesis is limited. The more the overlap, the more difficult the access.
In order to achieve generous overlap the surgeon may bring the sutures through the abdominal wall as shown in prior art FIGS. 4 and 5. The midpoint of a suture 3 may be tied to the edge of the prosthesis 1, and the two ends brought out directly through the abdominal wall 2 near one another, through a single small separate incision 4 in the skin 2a as shown in prior art FIG. 4. Both ends of this transmural suture 3 are then tied together, placing the knot 5 beneath the skin in the subcutaneous tissue 2b as shown in prior art FIG. 5. The skin incision 4 is closed separately with skin sutures 6 or staples (not shown). This process is completed around the periphery of the prosthesis.
If surgery is done by a minimally invasive technique (e.g. laparoscopic surgery), the surgeon's view is from within the abdominal cavity looking up at the anterior abdominal wall. The periphery of the prosthesis can be fixed to the abdominal wall by direct suture (using a laparoscopic suture technique), or by using one of several fixation devices, such as staples or helical tacks. Alternatively, sutures can be fixed to the prosthesis before it is introduced into the peritoneal cavity. Once the prosthesis is correctly positioned, both ends of these sutures can be pulled through the abdominal wall and the same small skin incision and the ends tied together, placing the knot subcutaneously. Transmural sutures provide the most secure fixation of prosthetic screens. Hernia recurrence rates are lower when transmural sutures are used. A combination of techniques, using a few transmural sutures, at equidistant points along the periphery of the prosthesis, with staples or helical tacks in between, is also useful.
Despite the many advances made in laparoscopic suturing techniques as well as in open hernia repair, there are still many problems to be overcome. One problem is that in order to secure the prosthesis to the abdominal wall at a single point with a transmural suture, each suture end must be pulled separately through the abdominal wall. This is time consuming. Another problem is that after placement of both ends of each suture through the abdominal wall, they must be clamped together above the body wall while other transmural sutures are placed, because it is much easier to place transmural sutures before the prosthesis is hoisted up against the abdominal wall. Clamping insures that suture ends do not inadvertently pull out of the abdominal wall during this process. A large number of clamps clutter the operative field and the sutures and clamps tend to entangle one another. Furthermore, multiple short skin incisions must be made to set the knot of each tied pair subcutaneously. This process is somewhat time consuming and the multiple skin incisions produce a poor cosmetic result. Moreover, when two strands of suture are tied subcutaneously to secure a prosthetic screen, tissues of the abdominal wall are captured and partially strangulated within the ligature. This often produces postoperative pain and cosmetically undesirable dimpling of the skin at the ligature sites.